Document Detail


Electrophysiological mechanisms of arterial muscle activation: alterations associated with cerebral vasospasm and hypertension.
MedLine Citation:
PMID:  3538027     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The active state of arterial muscle can be regulated by electrical events occurring at the plasma membrane. Factors which affect the level of the resting membrane potential can markedly alter resting tone, and sensitivity and contractility to agonists. The relative K+ conductance (gk) appears to be a principle factor in this regard. Reduction of gk induces generation of action potentials with concomitant mechanical activity. Cerebral arteries exposed to subarachnoid blood exhibit altered electrical and mechanical properties which predispose them to spasm; a phenomenon related to a reduced gk. Arterial muscle from hypertensive animals exhibit membrane electrical properties which may contribute to an elevated peripheral vascular resistance, namely, an elevated PNa/Pk ratio and altered electrogenic ion transport. Upon exposure to elevated transmural pressures, isolated cerebral arterial muscle cells depolarize and generate spontaneous "pacemaker-like" action potentials, processes which appear to be Ca2+ dependent. Cerebral arteries from spontaneously hypertensive rats depolarize more to elevated transmural pressures when compared to WKY. This increased membrane depolarization to pressure may be the result of an elevated Ca2+ permeability and/or an alteration in gk at the SHR arterial muscle cell membrane. Thus, abnormal activation of arterial muscle can be mediated by factors controlling transmembrane electrical gradients and ionic conductance systems.
Authors:
D R Harder
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.; Review    
Journal Detail:
Title:  Progress in clinical and biological research     Volume:  219     ISSN:  0361-7742     ISO Abbreviation:  Prog. Clin. Biol. Res.     Publication Date:  1986  
Date Detail:
Created Date:  1986-12-23     Completed Date:  1986-12-23     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7605701     Medline TA:  Prog Clin Biol Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  245-63     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Cerebral Arteries / physiopathology
Hypertension / physiopathology*
Ischemic Attack, Transient / physiopathology*
Muscle, Smooth, Vascular / physiopathology*
Grant Support
ID/Acronym/Agency:
HL-27862/HL/NHLBI NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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